Fall 2013 was our first large-scale studio implementation in the introductory physics course for life-science majors at Boston University. That semester, we observed a gender gap in both the three studio sections of the course and the two lecture sections that was similar to that observed at other places. Specifically, males, on average, did better than females. In spring 2013, we experimented with different seating arrangements in the three studio sections. One section had random groups, another had homogeneous groups, and the third had heterogeneous groups. We will report on the outcome of that experiment.